1. Field of the Invention
The present invention relates to a circuit arrangement for determining the distance of an aircraft from a VOR transmitter station, using a VOR receiver which determines the angular information of the VOR transmitter station perpendicular to the radial position line with an accuracy of .alpha. degrees from one bearing shift to the next.
2. Description of the Prior Art
A known VOR navigational system (VOR = very high frequency omni range) operates with a navigational receiver which incorporates two receiver sections. The first receiver section contains the reference phase, transmitted as a frequency modulation, in a demodulated form which serves as a reference signal. In a second receiver section, the rotational phase, which depends upon the particular direction of the antenna radiation pattern, occurs in the form of an amplitude modulated rotational signal. From a comparison of the reference phase with the rotational phase, the information concerning the azimuthal angle can be obtained.
The determination of the angular information can be effected to an accuracy of .alpha. degrees. A particularly simple circuit for determining accurate angular information, e.g. in increments of .alpha. = 1.degree., has been disclosed in U.S. patent application Ser. No. 574,633, filed May 5, 1975, corresponding to German Patent Application No. P 24 21 722.9 dated May 6, 1974 and entitled "Analyzer Device for a VOR Navigational Receiver."